Consider the glycolytic pathway starting with glu cose and ending with pyruvate
ID: 564761 • Letter: C
Question
Consider the glycolytic pathway starting with glu cose and ending with pyruvate What would be the affect on pyruvate concentration (i.e would the pyruvate concentration increase, decrease, or stay the same) under the situations given below? Provide a brief explanation (no more than 2 sentences) for each of your answers. a. Decrease in the ATP/AMP ratio. b. Increase in fructose-2,6-bisphosphate concentration. c. An increase in circulating insulin concentration. d. An increase in citrate concentration. e. Phosphorylation of pyruvate kinaseExplanation / Answer
In presence of high ATP concentration the Km of fructose 6-phosphate is increased, glycolysis thus turn off. AMP reverse the inhibitory action of ATP and so activity of enzyme increase when the ATP/AMP ratio lowered. Thus pyruvate concentration increases . Fructose 2,6 bisphosphate increases net flow of glucose through glycolysis by stimulating phosphofructokinase and by inhibiting fructose1,6 bisphosphatase , the enzyme that catalse this reaction in opposite direction.thus increase in Fructose 2,6 bisphosphate increases pyruvate concentration. Increse in insulin increases the glycolytic pathway by increasing concentration of Fructose 2,6 bisphosphate and inhibition of phosphofructokinase-2 Citrate inhibits phosphofructokinase by enhancing the inhibitory effect of ATP hence increase in citrate increase pyruvate concentration.